Applicants herein have, for a number of years, been actively engaged in the art of transparent armor manufacture and development. Such armor, as is well known in the art, consists of a laminate structure of one or more plies of glass and covered with a plastic ply of any suitable material having a high tensile strength. Such laminate structures have been constructed for bullet-proof windshields, screens and the like and consequently are most generally of a non-planar construction. Problems arising in developing such laminate structures result from the fact that total registry or congruency is necessary between the plies of the structure to provide for the requisite strength and optical characteristics.
To date, manufacturers of glass plies for transparent armor structures have formed the glass by utilizing a peripheral or picture frame mold whereby a flat glass sheet is secured about the periphery thereof and heated in an oven to its softening point. While remaining at this temperature for some period of time, a sag develops within the plate glass sheet and the forming process is thus achieved according to particular characteristics of the peripheral form. Critical problems have arisen utilizing such forms in that the amount of sag created in a glass sheet is dependent upon various parameters such as the temperature at which it is formed, the time duration of forming, and variations within the glass itself from lot to lot. Consequently, total registration or congruency between glass sheets is impossible and adherence thereto of the cast-formed plastic protective sheet is extremely difficult and expensive to achieve.
Heretofore in the art no approach has been taken to form such glass sheets with full-contact molds since a markoff or spalling effect is imparted to the glass sheets when molded upon a solid surface. For instance, if a planar glass sheet is placed atop a mold (either male or female) and heated so as to take the form of the mold, the frictional contact areas of the glass sheet with the solid mold will distort the glass and severely degrade the optical characteristics thereof. Even when using a peripheral mold as hereinabove mentioned, a spalling effect occurs about the periphery of the glass sheet where the same is held by the mold.
Consequently it is an object of the instant invention to provide a glass shaping form of the full-contact type for forming curvate glass elements for utilization in laminate structures.
It is another object of the invention to present a glass shaping form which is adjustable in nature so as to be conducive to the forming of any of numerous contours.
Yet a further object of the invention is to present a glass shaping form which is conducive to shaping glass into curvate and arcuate configurations while circumventing the aforementioned problems of mark-off and spalling.
Still another object of the invention is to present a glass shaping form which is simplictic in nature, adjustable and reliable in operation, and quite inexpensive with respect to prior art structures and techniques.
These objects and other objects which will become apparent as the detailed description proceeds are achieved by: a device for shaping planar sheets of glass into curvate configurations without spalling or mark-off comprising: a base; a plurality of threaded rods rotatably received within said base and vertically extending therefrom; a plurality of trunnion assemblies threadily engaged with each of said rods; support members interconnected between said trunnion assemblies; and a mold plate maintained atop said support members.